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Nuclear Perfusion Stress Test

A nuclear stress test measures a patient's blood flow two different ways--resting and exercising. What makes the test a nuclear stress test a perfusion test is that the patient is injected with a small amount of a radioactive isotope during the exercise portion of the test to aid doctors with viewing the heart and cardiovascular system.

  1. The Test

    • A stress test is a common way for doctors to measure heart rate and blood flow in heart patients. In a nuclear perfusion test, the patient exercises until reaching her maximum heart rate. Then doctors inject a small amount of radioactive material into the patient's bloodstream, where it reacts with the blood and travels to the heart.

    The Material

    • The radioactive material used during the test is considered a safe amount of radioactive material. The material is about 700 millirads. Thallium and Cardiolite are the two most common radioactive materials used during a nuclear perfusion stress test.

    How It Works

    • The radioactive material works as an enhancement when doctors take an image of the heart with a special scanner that can measure the size of heart walls and muscles. When blood forms normally, the heart's parts shows up as a dark spot. When blood flow is impeded, that part of the heart shows up as a light spot. It appears that way because the radioactive material has difficulty moving into that area due to blockage.

    What it Detects

    • The primary use of this stress test is to detect the narrowing of coronary arteries, which is a sign of coronary artery disease. This is one reason why patients that take this type of stress test usually have two images taken. The first comes shortly after the test and lasts about 30 minutes. The second occurs about 60 to 90 minutes after the first image and takes pictures of the body at rest.

    Preparing for the Test

    • Patients who are preparing for a nuclear stress test should adhere to all of their doctor's instructions. Generally, patients should not drink or eat six hours before the test, except for drinking water. Patients should not ingest caffeine 24 hours before the test. The patient should also consult with her doctor and make sure her regular medications will not interact adversely with any medication administered during the test. Since patients will be exercising, they should wear loose clothing.

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